Four follow-up questions:- @Dave Could you confirm Frank's comment that it's run as part of a boot-time scan?- How do you know it's been run 8 minutes after startup - I notice no harddrive activity? :S- Is there a separate log or results report to confirm nothing/something was found?- Would you recommend any complementary anti-rootkit products as an additional security?

The indication it has been run is located at (normally) C:\Program Files\Alwil Software\Avast4\DATA\logand the title is aswAR.log. (opens in notepad.)As to the other three questions, I couldn't say. I've not noticed extra HDD activity 8 minutes after start, but nor have I especially listened/watched for it.The rootkit scanner is based on the GMER application, which I think is respected and capable. Extra demand scanner/s are up to you. My choice would be not to bother if there was no indication of anything found. Maybe a checkup (second opinion) scan with a few demand scanners of different categories (AV, AS, Rootkit) every few months. So far I've not found anything significant by following that protocol. The odd FP; the odd tracking cookie. So I'm reasonably confident that the various modules in Avast do a pretty decent job. Actually, a very decent job.

Four follow-up questions:- @Dave Could you confirm Frank's comment that it's run as part of a boot-time scan?- How do you know it's been run 8 minutes after startup - I notice no harddrive activity? :S- Is there a separate log or results report to confirm nothing/something was found?- Would you recommend any complementary anti-rootkit products as an additional security?

1. If I could I would have at the time, to find out I would have run a boot-time scan and checked out the aswAr.log file mentioned by Trag57. You would have to be quick in checking as 8 minutes after boot it would run and overwrite the previous log.2 & 3. As Targ57 mentioned.4. I have a few I would try if I felt that I may have a rootkit, but since they will be constantly updated keeping a copy of them is of limited use as it is best to get the latest version before you run it.

There are more anti-rootkit scanners than you can shake a stick at but the greatest majority are totally user unfriendly as they present the user with more questions than answers. There are very few that I would consider efficient and relatively user friendly, but even then you may need further advice.

GMER (and to a degree Rootkit Revealer) as mentioned is very powerful, but a little like the hijackthis of anti-rootkits as it produces volumes of data that you have to analyse. So these to my mine aren't for your average user.